daniel alexander (alexandd at vax.sbu.ac.uk) wrote:
: A friend of mine saw a documentary on this and asked me to find out
: something about it...I was rudely sceptical, but does anyone know
: where I can find something to put his mind at rest? Cheers
: Reply to alexandd at vax.sbu.ac.uk
Dear Daniel,
So far, all the responses refer to water's memory (?) of dissolved
substances. On the off chance that this was not what your friend had in mind,
there is a phenomenon whereby eddies in the water "remember" the angular
momentum imparted when the water filled a vessel. This very real effect
accounts for the direction the water rotates when one pulls the stopper
out of the vessel (or flushes it). Calculations show that Corriolus force
is not the determining factor, and that not all situations result
in clockwise flow in the Northern hemisphere. You can do the experiment
by filling a tub using a hose or faucet whose orientation can be changed
to produce either clockwise or counter-clockwise rotation when filling.
Varying the time between filling and emptying will tell how soon the water
forgets.
Yours,
Bill Tivol
